Related papers: Dwarf Galaxies Also Have Stellar Halos
The halo of the Milky Way provides unique elemental abundance and kinematic information on the first objects to form in the Universe, which can be used to tightly constrain models of galaxy formation and evolution. Although the halo was…
If dwarf galaxies are primeval objects in the Universe, as hierarchical galaxy formation scenarios predict, they should show traces of their old stellar populations, perhaps distributed in extended, differentiated structures. The working…
The standard cold dark matter (CDM) model has recently been challenged by the claim that dwarf galaxies have dark matter halos with constant density cores. Consequently, numerous alternative dark matter candidates have recently been…
The balance of evidence indicates that individual galaxies and groups or clusters of galaxies are embedded in enormous distributions of cold, weakly interacting dark matter. These dark matter 'halos' provide the scaffolding for all luminous…
We found that 10 metal-poor globular clusters are greately distinguished for anomalously small masses on the "destruction rate--mass" plain. As it turned out, these poor clusters, situated 15 kpc farther from the Galactic centre, are…
In a purely cold dark matter universe, the initial matter power spectrum and its subsequent gravitational growth contain no special mass- or time-scales, and so neither do the emergent population statistics of internal dark matter (DM) halo…
We explore mechanisms for the regulation of star formation in dwarf galaxies. We concentrate primarily on a sample in the Virgo cluster, which has HI and blue total photometry, for which we collected H$\alpha$ data at the Wise Observatory.…
We examine correlations between the masses, sizes, and star formation histories for a large sample of low-redshift early-type galaxies, using a simple suite of dynamical and stellar populations models. We confirm an anti-correlation between…
We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…
We use a robust analytical model together with a high-resolution hydrodynamical cosmological simulation to demonstrate that in a $\Lambda$ cold dark matter ($\Lambda$CDM) universe, a small fraction of dwarf galaxies inhabiting dark matter…
We use a series of high-resolution N-body simulations of a `Milky-Way' halo, coupled to semi-analytic techniques, to study the formation of our own Galaxy and of its stellar halo. Our model Milky Way galaxy is a relatively young system…
Clumped dark matter arises naturally within the framwork of generic cosmological dark matter models. Invoking the existence of dark matter clumps can also solve may unexplained mysteries in astrophysics and geology or geophysics, eg. the…
Dwarf spheroidal (dSph) galaxies are considered the basic building blocks of the galaxy formation process in the LCDM (Lambda Cold Dark Matter) hierarchical cosmological model. These galaxies are believed to be the most dark matter (DM)…
It has been recently claimed that the confined structure of the debris from the Sagittarius dwarf implies that the dark-matter halo of our Galaxy should be nearly spherical, in strong contrast with predictions from cold dark-matter (CDM)…
Recent high-resolution simulations of the formation of dark-matter halos have shown that the distribution of subhalos is scale-free, in the sense that if scaled by the velocity dispersion of the parent halo, the velocity distribution…
We obtained comprehensive sets of elemental abundances for eleven damped Ly-alpha systems (DLAs) at z_DLA=1.7-2.5. In Paper I of this series, we showed for three DLA galaxies that we can derive their star formation histories and ages from a…
We examine the observational consequences of the two possible origins for irregular galaxies: formation from collapse of a primordial cloud of gas early in the age of the Universe, and formation from tidal tails in an interaction that could…
The nature of the dark matter in the Halo of our Galaxy remains a mystery. Arguments are presented that the dark matter does not consist of ordinary stellar or substellar objects, i.e., the dark matter is not made of faint stars, brown…
I discuss the chemical evolution of star clusters, with emphasis on old globular clusters, in relation to their formation histories. Globular clusters clearly formed in a complex fashion, under markedly different conditions from any younger…
We present sensitive and high resolution 21 cm observations of the dwarf irregular (dIm) galaxy DDO 43, in conjunction with optical broad and narrow band images in U, B, V, and Halpha. The observations are used to examine the relationship…